It is known that isopropyl (2E,4E)-3,7,11-trimethyl-11-methoxy-2,4-dodecadienoate (referred to furtheron as methoprene) exhibits useful insecticidal effects (U.S. Pat. No. 3,904,662).
According to U.S. Pat. No. 3,912,815 polymeric capsules comprising methoprene can be used for the extermination of undeveloped insects living on or under the surface of soil.
According to J. Eco. Entomol. 67, 69-70 (1974) methoprene as a juvenile hormone estergase inhibiting substance when applied onto the larvae of different Diptera species is capable of inhibiting the energence of the imagos from the nymphs. The effective concentration of methoprene might vary depending on the larvae of the different species. According to in vitro tests 10 ppm of methoprene added to the dung completely inhibits the energence of imago from the nymphes formed from the larvae of the Musca autumnalis species. In the case of Musca domestica a concentration of 100 ppm resulted in an inhibition of 90%. A similar effect was observed on the larvae of Stomoxys calcitrans too, while methoprene proved to be the most effective against the larvae of Haematobia irritans. Due to its high activity and very low toxicity methopren can enter the excrement by feeding the methoprene to the animals. On oral administration the following activity was found against the most important fly species.
Haematobia irritans.sup.1 : 0.002 mg/kg body weight/day, 100% effect; PA0 Stomoxys calcitrans.sup.2 : 0.4 mg/kg body weight/day, 100% effect; PA0 Musca autumnalis.sup.2 : 0.5 mg/kg body weight/day, 99% effect; PA0 Musca domestica.sup.3 : 10.0 mg/kg body weight/day, 80% effect FNT (1) R. L. Harris, E. D. Frazer and R. L. Younger: J. Eco. Entomol. 66, 1099-1102 (1973), FNT (2) R. W. Miller, L. G. Pickens; J. Eco. Entomol. 68, 810-812 (1975), FNT (3) R. W. Miller, E. C. Uebel: J. Eco. Entomol. 67, 69-70 (1974).
According to hitherto applied practical methods cattle ingest methoprene either dissolved in the drinking water or admixed with the salt or proteine fodder. The drawback of consumption of the drinking water is that uniform concentration can only be ensured by using expensive specific equipment. The safest ingestion in the form of a solid nutriment consists of the addition of methoprene to mineral salt additives since said additives are more widespreadly used in cattle husbandry than other feed additives. At the same time said use encounters difficulties because as a result of chemical lability of methoprene the active ingredient content of said compositions decreases very rapidly, particularly when used for cattle grazing on pasture land, where the weather conditions--first of all sunshine--accelerate the chemical decomposition to a large extent. Thus, according to J. Eco. 67, 384-386 (1974) the active ingredient content of salt blocks comprising 0.9% of methoprene and stored in a store-house for 9 weeks decreases by 13-30%. According to J. Eco. Entomol. 71, 274-278 (1978) in a salt mixture stored under field conditions the average decrease of the active ingredient content within 10 days amounts to 26%.